A cost effective apparatus used for a closure in a pressure vessel is needed for a variety of applications. In the past, when a guided ring is used on a manually operated vessel closure, there is a possibility that the operator may inadvertently extend the rings with the door in the open position. This action creates a potential for damage to occur if the operator attempts to close the door while the ring segments are extended. The ring segments make contact with the vessel wall external surface which can damage either the ring segments, the vessel wall, or the guide rods.
Closures which require a high level of machining and/or automation to accomplish the safe operation of a pressure vessel have been used frequently in low volume equipment such as dry cleaning using liquid carbon dioxide. The apparatus described herein improves on the previous attempts to accomplish the safe closure of pressure vessels.